1. Field of the Invention
This invention pertains to a composition that may be a component of a compound used to make mechanical rubber goods such as tires and belts. The invention is particularly suited for use in applications where a high strain environment is encountered.
2. Description of Related Art
U.S. Pat. No. 4,514,541 to Frances pertains to a particulate elastomeric composition having a density ratio of 0.1 to 0.4 comprising 5-75% by weight of an elastomer, 15-65% by weight of a filler and 10-60% by weight of aramid pulp and a solution process for its preparation. The composition is useful as a masterbatch for the introduction of aramid pulp into elastomeric articles.
U.S. Pat. No. 8,211,272 to Levit and Amma relates to para-aramid pulp including meta-aramid fibrids for use as reinforcement material in products including for example friction materials, fluid sealing materials, and papers. The invention further relates to processes for making such pulp.
There is an ongoing need to have rubber-fibrous pulp composites that have a yield strain of at least 70%, a yield stress of at least 4 MPa and a percentage elongation of at least 200% or even 300%. The use of such composites in high strain tires is highly desirable.
Previous attempts to achieve this by using higher aramid pulp concentrations, fiber dispersing agents, and interface modifiers led to decreased yield strain. Ming et. al. (J. Appl. Polymer Sci. 120, 1439, 2011) studied composites made using different types of rubber, Kevlar® fiber, and fibrillar silica. Their results showed a yield strain of less than 50%.